Immunoglobulin biosynthesis in myeloma-associated and casein- and endotoxin-induced murine amyloidosis

Amyloidosis was induced in C57BL mice by daily injections of casein and in BALB/c mice by daily injections of endotoxin. There was no obvious disorder of immunoglobulin biosynthesis by spleen lymphocytes in these mice either before, during the development of, or in the amyloidotic stage. The pattern of immunoglobulin synthesis, assembly, and secretion was unaltered, the relative amount of heavy and light chains produced was normal, and there was an absence of immunoglobulin polypeptide chain fragments. Small amounts of amyloid were present in only 1 of 19 BALB/c and C3H mice (the IgG2a producing MOPC 173 tumor) bearing immunoglobulin-producing myeloma tumors and variants of these tumors. There was no relationship between excess light chain production by tumor plasma cells or spleen lymphocytes and the development of amyloidosis and there were no light chain fragments demonstrable. Antiserum prepared against casein-induced amyloid cross-reacted by immunofluorescence with the amyloid present in the MOPC 173 tumor-bearing mice, indicating the presence of common antigenic determinants in these two forms of amyloid. Attempts to study the biosynthesis of amyloid with incorporation of radioactively labeled amino acids were unsucessful.